Modern vehicles, such as aircraft, often include head-up displays (HUDs) that project various symbols and information onto a transparent display, or image combiner, through which a user (e.g., the pilot) may simultaneously view the exterior or a display device, such as an liquid crystal display (LCD), on which a digital representation of the terrain outside the aircraft is shown. Traditional HUDs incorporate fixed image combiners located above the instrument panel on the windshield of the aircraft, or directly between the windshield and the pilot's head.
Over the years, near-to-eye (NTE) displays have been developed that typically include an image combiner in close proximity to the user's eye and in a fixed position relative to the user's head. As such, NTE displays are also often referred to as helmet-mounted-displays (HMDs), head-mounted-displays (also HMDs), head-worn-displays (HWDs), or by other names or acronyms. Many applications which utilize these displays rely in part on knowing the detailed viewing geometry. Typically, this is accomplished with a system referred to as a “head tracker” or “tracking assembly.” While head position and orientation may be important, it is often even more beneficial to know the specific position and orientation of the display unit or ocular (i.e., the NTE display screen) itself, as opposed to the head of the user.
Many tracking methods have been developed and utilized. For example, magnetic trackers have long been utilized in military applications. Recently, much interest has been shown in optical trackers that utilize multiple light sources and light detectors in a variety of geometries. One drawback of current optical trackers is that in order to accurately track the motion of the NTE display itself, the NTE display often includes large and bulky components that reduce the user's comfort.
Accordingly, it is desirable to provide an improved method and system for operating a NTE display which allows for a simpler, smaller, and lighter headset assembly. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.